<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" href="css/demo4.css">
</head>
<body>


<!--浮动-->
<!--<div class="box">-->
    <!--<div class="box1">box1</div>-->
    <!--<div class="box2">box2</div>-->
    <!--<div class="box3">box3</div>-->

<!--</div>-->


<div class="box10">
    <div class="box11">box11</div>
    <div class="box22">box22</div>
    <div class="box33">box33</div>

</div>

</body>
</html>